TWI838490B - Time of flight-based three-dimensional sensing system - Google Patents

Abstract

A light shaping optic may include a substrate. The light shaping optic may include a structure disposed on the substrate, wherein the structure is configured to receive one or more input beams of light with a uniform intensity field and less than a threshold total intensity, and wherein the structure is configured to shape the one or more input beams of light to form one or more output beams of light with a non-uniform intensity field and less than the threshold total intensity.

Description

Time-of-flight based 3D sensing system

This application relates to a time-of-flight based three-dimensional sensing system.

The measurement system may be used for depth sensing measurements. For example, a lidar system may transmit a pulse of laser light and may measure the reflected pulse to determine the distance of an object from the lidar system. In this case, the lidar system may perform a time-of-flight measurement of the laser pulse and may produce a three-dimensional representation of the object. A flash lidar system uses an illumination device and an optical light shaping element that illuminates a scene (the field of view of the flash lidar system) with a single pulse. In this case, the flash lidar system may use time-of-flight measurements of reflections of a single pulse of the light beam to produce a three-dimensional representation of the scene. A scanning (or sweeping) lidar system may use an illumination unit, an optical shaping element, and one or more active mirrors to move multiple pulses of a laser beam across a scene. For example, the optical light shaping element may spread each pulse of the laser beam into a line, and the active mirror may sweep the line across the scene over the multiple pulses of the laser beam. In this case, the scanning lidar system may use multiple measurements of reflections from the multiple pulses of the laser beam to produce a three-dimensional representation of the scene.

According to some possible implementations, a light shaping optical element may include a structure, wherein the structure is constructed to receive one or more input light beams having a uniform intensity field and a total intensity less than a critical intensity, and wherein the structure is constructed to shape the one or more input light beams to form one or more output light beams having a non-uniform intensity field and a total intensity less than the critical intensity.

In a light shaping optical element, a non-uniform intensity field comprises a set of higher intensity light regions and a set of lower intensity light regions. The non-uniform intensity field is at least partially illuminated. In the light shaping optical element, at least a portion of the non-uniform intensity field is not illuminated. In the light shaping optical element, the non-uniform intensity field forms a pattern, and wherein the pattern is at least one of: a dot pattern, a grid pattern, a ring pattern, an interference pattern, a step pattern, a sawtooth pattern, a continuous pattern, a sine-based pattern. In the light shaping optical element, one or more input light beams are uniform scan lines of a lidar system, and one or more output light beams form non-uniform scan lines of the lidar system.

According to some possible implementations, a system may include an optical transmitter for providing a light beam directed toward an object, wherein the light beam is associated with a constant intensity across a field of view. The system may include a light shaping optical element for focusing the light beam into one or more focusing regions, wherein the one or more focusing regions of the field of view are associated with a higher light concentration than one or more other regions of the field of view. The system may include an optical receiver for receiving reflections of the light beam reflected from the object and performing a plurality of time-of-flight measurements on the light beam. In the system, the light shaping optical element is an engineered diffuser. The system is constructed to illuminate the object using the light beam such that the object is unevenly illuminated by the one or more focusing regions. In the system, an optical receiver is constructed to perform a time-of-flight measurement for each of one or more focus areas of the field of view. The system further includes a processor, the processor being constructed to generate a depth point cloud of an object using a plurality of time-of-flight measurements. In the system, the one or more focus areas of the field of view form a plurality of intensity points; and the plurality of intensity points are associated with a critical density. In the system, the system is constructed to determine that the plurality of time-of-flight measurements are greater than a critical distance of the system relative to the object. In the system, an intensity of the light beam meets an eye safety level threshold. The system further includes a processor for generating a three-dimensional representation of the object based on a plurality of time-of-flight measurements and an imaging measurement of another light beam provided by the optical transmitter, wherein the other light beam is associated with a constant intensity and is directed toward the object without being shaped into one or more focusing regions. In the system, the optical receiver is a sensor array including a plurality of sensor elements; and each sensor element of the plurality of sensor elements is constructed to generate a time-of-flight measurement of the plurality of time-of-flight measurements.

According to some possible implementations, the optical device may include a substrate. The optical device may include one or more optical transmitters disposed on the substrate. The optical device may include a light shaping optical element disposed in the optical path of the one or more optical transmitters to provide an uneven patterned intensity light beam to an object to achieve three-dimensional measurement of the object. The optical element is a component of a lidar system. The optical element further includes an array of sensor elements disposed on the substrate. In the optical element, the array of sensor elements is constructed to determine a plurality of flight time measurements of the uneven patterned intensity light beam to determine a plurality of distances associated with the object.

The following detailed description of exemplary embodiments refers to the accompanying drawings. The same element symbols in different drawings can identify the same or similar elements. The following description uses a lidar system as an example, however, the calibration principles, procedures and methods described herein can be used with any sensor, including but not limited to other optical sensors.

A three-dimensional imaging system such as a lidar system may provide a uniform intensity field to enable imaging of objects in a field of view. For example, a flash lidar system may transmit a uniform intensity field of the field of view (i.e., the field of view of the flash lidar system), and measurements of reflections of the uniform intensity field may be performed to produce a three-dimensional representation of the object. Similarly, a scanning lidar system may provide a set of uniform intensity field scan lines to scan across the field of view, and measurements of reflections of the set of uniform intensity field scan lines may be performed to produce a three-dimensional representation of the object.

However, the intensity of light provided by the three-dimensional imaging system may be limited to less than a critical intensity. For example, compliance with eye safety rating requirements may prevent the three-dimensional imaging system from providing light intensities exceeding a critical value. The eye safety threshold may be based on power, divergence angle, pulse duration, exposure direction, wavelength, and/or the like. Similarly, power capacity limitations in increasingly miniaturized devices (such as cell phones) may limit the light intensity that a three-dimensional imaging system can provide. Therefore, at distances greater than the critical distance from an object, the amount of light reflected back to the three-dimensional imaging system for measurement may be insufficient to enable accurate measurement to be performed. For example, when a lidar system attempts to determine the distance to a set of objects in its field of view, some objects may be within a critical distance and may be accurately depth-sensed by the lidar system, while other objects may be beyond the critical distance and the lidar system may not receive enough reflected light for accurate depth sensing.

Some embodiments described herein may use a non-uniform intensity field to perform three-dimensional imaging. For example, an optical system may include: an optical transmitter that provides a uniform intensity field; and an optical light shaping element or light shaping optical element that is used to shape the uniform intensity field into a non-uniform intensity field. In this case, by using a non-uniform intensity field, the optical system may enable light greater than a critical intensity to be directed toward some parts of the field of view, and less than a critical amount of light to be directed toward other parts of the field of view. For example, the optical system may enable a light collection area to include light greater than a critical intensity, which may enable an increased range for accurate depth sensing. In this way, optical systems can achieve three-dimensional measurements at greater distances than using a uniform intensity field without exceeding a critical light intensity across the field of view. Furthermore, by shaping a non-uniform intensity field with multiple focusing regions as described herein, optical systems can achieve an increased large range for depth sensing and can reduce the resolution loss associated with focusing relative to, for example, laser ranging systems that transmit a single focused laser pulse to perform ranging.

1A and 1B are diagrams of an exemplary embodiment 100 described herein. As shown in FIG. 1A and 1B , the exemplary embodiment 100 may include a sensor system 105 for performing three-dimensional measurement on an object.

As shown in FIG1A , the sensor system 105 may include a transmitter system 110, which may include an optical transmitter 115 and a light shaping optical element 120, and a receiver system 125, which may include an optical receiver 130 and one or more other optical elements, such as a filter 135, a lens 140, and/or the like. In some embodiments, the sensor system 105 may include a processor to process one or more measurements performed by the optical receiver 130. In some embodiments, the sensor system 105 may include one or more other optical transmitters 115 and/or one or more other optical receivers 130 to provide and measure multiple light beams having different characteristics, such as different types of light fields, as described in more detail herein. In some implementations, the sensor system 105 can be in a mobile device, a mobile phone, a security device, a robotic device, a lidar device, an autonomous vehicle system, a gesture recognition system, a proximity sensor system, a counting system, and/or the like.

In some embodiments, the sensor system 105 may be a distance sensing system. For example, the sensor system 105 may be a lidar system (e.g., a flash lidar system, a scanning lidar system, and/or the like), a depth sensor, and/or the like. In some embodiments, the sensor system 105 may be a three-dimensional imaging system. For example, the sensor system 105 may be configured to determine a two-dimensional image of an object and one or more distances associated with the object and/or one or more parts of the object to generate a three-dimensional representation of the object. In this case, the sensor system 105 may be configured to combine the two-dimensional image of the object with the distances of the object and/or one or more parts thereof to generate a three-dimensional representation.

In some embodiments, the optical transmitter 115 may be a laser, a light emitting diode (LED), and/or the like. For example, the optical transmitter 115 may be a laser that is constructed to provide a light beam with a uniform intensity field for time-of-flight distance determination. Additionally or alternatively, the optical transmitter 115 may include a vertical cavity surface emitting laser (VCSEL). In some embodiments, the optical transmitter 115 may provide multiple light beams. For example, the optical transmitter 115 and the light shaping optical element 120 may be integrated. In this case, a single substrate may include one or more optical transmitters 115 and one or more light shaping optical elements 120.

In some embodiments, the optical transmitter 115 may be a transmitter of a spectral recognition system, an object recognition system, an imaging system, a motion tracking system, a biometric system, a security system, and/or the like. In some embodiments, the optical transmitter 115 may transmit a light beam associated with a specific spectral range. For example, the optical transmitter 115 may transmit light in the visible range, the near infrared range, the mid-infrared range, the LiDAR range, and/or the like. Although some embodiments are described according to a set of specific spectral ranges, other spectral ranges may also be possible.

In some implementations, the optical receiver 130 may be a sensor array including multiple sensor elements to perform multiple measurements of the reflected light beam or its portion. For example, the optical receiver 130 may include multiple sensor elements disposed on a substrate to receive multiple light beams or multiple portions of a single light beam.

In some embodiments, the light shaping optical element 120 can be constructed to diffuse or shape a uniform intensity field into a non-uniform intensity field in a particular pattern, as described in more detail herein. In this way, by focusing the photons of the light beam at a particular area of the scene, the number of photons returned to the optical receiver 130 at the particular area of the scene is increased, thereby enabling time-of-flight measurements with greater accuracy, at greater distances, and/or in denser ambient light conditions than using a uniform intensity field. In some embodiments, the light shaping optical element 120 distributes the pattern of dots in a non-uniform density to produce the non-uniform intensity field.

In some embodiments, the light shaping optical element 120 may be a specific type of optical element with a specific structure. For example, the light shaping optical element 120 may be and/or include an optical diffuser, a filter, a collimator, a lens, a reflector, a diffuser (e.g., an engineered diffuser, a holographic diffuser, etc.), another optical element, and/or the like. In some embodiments, the light shaping optical element 120 may be a diffractive optical element (DOE) to diffract the light provided by the optical transmitter 115 to form a non-uniform intensity field. In some embodiments, the light shaping optical element 120 may be a refractive optical element (DOE) to refract the light provided by the optical transmitter 115 to form a non-uniform intensity field. In some implementations, the light shaping optical element 120 may be a set of micro lenses to shape the light provided by the optical transmitter 115 to form a non-uniform intensity field. In some implementations, the light shaping optical element 120 may change the divergence of the light beam to form a non-uniform intensity field.

In some embodiments, the light shaping optical element 120 may be an engineered diffuser that can provide feature sizes between about 100 and 1000 times greater than those achievable with a DOE (e.g., about 20 micrometers (μm) with a depth of less than 80 μm), reduced manufacturing errors, and/or the like. Additionally or alternatively, the use of an engineered diffuser can provide divergence angle flexibility between about 0.25 degrees and 150 degrees. In some embodiments, the light shaping optical element 120 may be a rectangular distributed engineered diffuser, a circular distributed engineered diffuser, and/or any other shape of distributed engineered diffuser. In this case, the light shaping optical element 120 may be patterned and/or formed on, for example, a glass substrate having a thickness of about 0.3 millimeters (mm), between 0.1 mm and 0.01 mm, and/or the like. Additionally or alternatively, the light shaping optical element 120 may be embossed onto a substrate attached to a substrate, and/or the like. Additionally or alternatively, the light shaping optical element 120 may be independent of the substrate and may be formed from one or more components of an optical component. In some embodiments, the light shaping optical element 120 may have a non-planar shape.

In some embodiments, the light shaping optical element 120 may be optically coupled to a plurality of optical transmitters 115 to enable generation of a non-uniform intensity field. Additionally or alternatively, the plurality of light shaping optical elements 120 may direct a plurality of beams or a plurality of portions of a single light beam toward a common area to generate a non-uniform intensity field. In some embodiments, the light shaping optical element 120 may include a plurality of light shaping optical elements (e.g., a plurality of different light shaping optical elements) to form a single pattern of non-uniform intensity field light, a plurality of different patterns of non-uniform intensity field light, a uniform intensity field light (e.g., used in combination with a non-uniform intensity field light), and/or the like. In some embodiments, the plurality of light shaping optical elements 120 may be optically coupled to a plurality of optical transmitters 115 to form a single pattern, a plurality of patterns, and/or the like. Additionally or alternatively, a single light shaping optical element 120 may be optically coupled to a single optical transmitter 115, a single light shaping optical element 120 may be optically coupled to multiple optical transmitters 115, multiple light shaping optical elements 120 may be optically coupled to a single optical transmitter 115, and/or the like.

In some implementations, the light shaping optical element 120 may be associated with and/or include one or more layers that provide one or more other functions. For example, the light shaping optical element 120 may include and/or be coupled to a bandpass filter layer, a long pass filter layer, a short pass filter layer, an anti-reflection coating, a focusing layer, an optical transmission conductive layer, and/or the like.

As further shown in FIG. 1A and by reference numeral 145, the optical transmitter 115 can transmit an input light beam toward the light shaping optical element 120. For example, the optical transmitter 115 can transmit an input light beam having a uniform intensity field. In this case, the input light beam can be associated with less than a critical intensity, such as less than an eye safety rating threshold (e.g., less than a critical power associated with an eye safety rating, such as less than a power less than a critical value at a given divergence angle, pulse duration, exposure direction, wavelength, and/or the like), less than a threshold value associated with power capacity, and/or the like. In some cases, the threshold power may be related to a particular class of optical transmitters, such as a power threshold for a class 1 laser, a class 2 laser, a class 3 laser, and/or the like. In some implementations, the threshold intensity may be related to the total intensity of a uniform intensity field. Additionally or alternatively, the threshold intensity may be related to the net intensity, average intensity, maximum intensity, and/or the like of a uniform intensity field. In some implementations, the input beam may be associated with an intensity greater than a threshold (e.g., regarding eye safety). In this case, the light shaping optical element 120 and/or one or more other optical elements may reduce the intensity of the output beam, as described herein, so that it has an intensity less than the threshold over the entire illumination field of the output beam. In some embodiments, the input beam may have a constant intensity. In some embodiments, the input beam may have an intensity that is constant within a critical portion of a uniform intensity field (e.g., the intensity is constant within the central 95% of the uniform intensity field and gradually decreases at the edges).

As further shown in FIG. 1A , the light shaping optical element 120 can shape an input light beam to form an output light beam having a specific pattern that is directed toward the object 150. For example, the light shaping optical element 120 can focus the input light beam, diffuse the input light beam, induce an interference pattern in the input light beam, and/or the like. In this way, the light shaping optical element 120 can direct the output light beam with a non-uniform intensity field. For example, the light shaping optical element 120 can direct a set of discrete illumination points toward the object 150, which can each be a separate output light beam (beam portion of the output light beam). Additionally or alternatively, the light shaping optical element 120 may form an output beam having a set of focusing regions in the field of view of the output beam and another set of regions in the field of view of the output beam in which the output beam is associated with a relatively higher light intensity and in which the output beam is associated with a relatively lower light intensity, as described in more detail herein. In this case, the output beam may be in the form of a single output beam with varying intensity, multiple output beams with varying intensity, multiple output beams with different intensities, and/or the like. Additionally or alternatively, the light shaping optical element 120 may form other types and configurations of focusing regions, such as a grid configuration, an interference pattern configuration, and/or the like, as described in more detail herein.

As shown in FIG. 1B with reference numeral 155, based on one or more output light beams being directed toward object 150, reflections of the output light beams may be directed toward receiver system 125. For example, reflections of the output light beams may be collected, filtered, shaped, and/or the like by lens 140 and filter 135, and may be received by optical receiver 130. In this case, optical receiver 130 may receive a portion of the set of output light beams reflected from object 150 using an array of sensor elements. In this case, each portion of the output light beams may correspond to a concentrated area of light, and optical receiver 130 may use the sensor elements to perform a time-of-flight measurement associated with each concentrated area. Additionally or alternatively, optical receiver 130 may receive multiple reflected light beams. For example, when the light shaping optical element 120 causes the plurality of discrete output light beams to be directed toward the object 150, the optical receiver 130 may receive reflections of the plurality of discrete output light beams. In some implementations, the optical receiver 130 may be disposed behind the lens 140, and multiple reflections of the plurality of output light beams may pass through the lens 140 and the filter 135 before being received by the optical sensor. Additionally or alternatively, the lens 140 and the filter 135 may not be disposed in the optical path between the object 150 and the optical receiver 130. Although some implementations described herein are described in terms of free space optics configurations, other implementations may also be possible, such as integrating the transmitter system 110, the receiver system 125, and/or the like into a single common substrate.

1B and as further shown by reference numeral 160, the sensor system 105 may determine one or more three-dimensional measurements of the object 150. For example, the optical receiver 130 and/or a processor associated therewith may perform one or more time-of-flight measurements on the reflection of the output beam of light and may determine the distance of the object 150 and/or one or more portions thereof from the sensor system 105. In this case, the optical receiver 130 and/or a processor associated therewith may determine the distance of the object 150 and/or portions thereof from the sensor system 105 based on the one or more time-of-flight measurements and may generate a three-dimensional measurement of the object 150 based on the distance of the object 150 and/or portions thereof from the sensor system 105. In some implementations, the sensor system 105 may perform direct time-of-flight measurement (e.g., by measuring time), gated time-of-flight measurement (e.g., by using a shutter structure, such as an electric shutter, to open and close a gate), indirect time-of-flight measurement (e.g., by measuring phase), and/or the like.

In some implementations, the sensor system 105 can generate a depth point cloud of the biological object 150. For example, when the sensor system 105 provides a non-uniform intensity field having a plurality of intensity points in a dot pattern, as described in more detail herein, the sensor system 105 can generate a depth point cloud representing a plurality of distance measurements of a plurality of portions of the object 150 illuminated by the plurality of intensity points in the dot pattern. In this case, by providing a critical density of intensity points in the field of view, the sensor system 105 achieves a critical level of resolution of the generated three-dimensional representation of the object 150.

In some implementations, the sensor system 105 may combine multiple sets of measurements to produce a three-dimensional measurement or three-dimensional representation of the object 150. For example, the sensor system 105 may provide another light beam with uniform intensity to the object 150 to perform two-dimensional imaging of the object 150, and may combine the two-dimensional imaging with one or more time-of-flight-based distance measurements of the object 150 to produce a three-dimensional representation of the object 150. In this way, the sensor system 105 may use a single light beam to achieve three-dimensional imaging. Additionally or alternatively, the sensor system 105 may use the same light beam as the time-of-flight measurement to perform two-dimensional imaging. For example, the sensor system 105 may determine both time-of-flight measurements and imaging measurements about the reflection of the output light beam to achieve three-dimensional imaging of the object 150. In this way, the sensor system 105 can perform three-dimensional imaging without directing separate light beams toward the object 150, which can reduce the size and/or cost associated with the sensor system 105.

As indicated above, Figures 1A and 1B are provided only as one or more examples. Other examples may be different from the examples described with respect to Figures 1A and 1B.

Figures 2A to 2G are diagrams of exemplary implementation schemes 200-250 of non-uniform intensity light fields that can be shaped by the light shaping optical element 120.

As shown in FIG2A , exemplary implementation 200 illustrates an example of a non-uniform intensity field. As shown by graph 202, the non-uniform intensity field may include discrete regions 204 of higher intensity light and discrete regions 206 of lower intensity light (e.g., zero intensity light) in a stepped pattern. In other words, some areas of the field of view are illuminated by the output beam, while other areas of the field of view are illuminated by the output beam. In this case, discrete regions 204 may be concentrated areas of the illuminated field of view, while discrete regions 206 may be unilluminated areas of the field of view. In some cases, each point shown in FIG2A may actually represent multiple points concentrated into a particular area. For example, light shaping optics may focus multiple points into each area of the field of view to focus light in each area of the field of view rather than providing a uniform distribution of light points across the field of view.

In this way, the non-uniform intensity field can form a pattern of dots (i.e., where each dot represents a light beam or a portion thereof) to focus the light beam and illuminate an object unevenly with the light beam, thereby increasing the range of depth sensing measurements that the sensor system 105 can perform relative to a uniform intensity field produced by passing the light through a diffuser. In some embodiments, discrete regions 204 of higher intensity light can be associated with intensities that exceed a threshold value, while discrete regions 206 of lower intensity light can be associated with intensities that do not exceed the threshold value, such that the total intensity of the light beams forming the non-uniform intensity field is less than the threshold value. In this way, the sensor system 105 can increase the range of depth sensing without the total intensity of the light exceeding the threshold value. In another example, the sensor system 105 may provide a grid pattern, a stripe pattern, and/or the like for the non-uniform intensity field instead of a dot pattern.

As shown in FIG2B , exemplary embodiment 210 illustrates another example of a non-uniform intensity field. As shown by graph 212, the non-uniform intensity field may include discrete regions 214 of higher intensity light and discrete regions 216 of lower intensity light (e.g., zero intensity light) in a step pattern. In another example, the non-uniform intensity field may be a sawtooth pattern rather than a step pattern. In this case, each discrete region 214 may be associated with a plurality of different light intensities, as shown by graph 212. In this manner, the non-uniform intensity field increases the size of the dots of the dot pattern, thereby increasing the resolution of three-dimensional measurements of an object relative to, for example, a smaller dot size. In some embodiments, the light shaping optical element can produce points, lines, or patterns in accordance with the cosine law of radiation measurement, where the centers of the points, lines, or patterns are not equal in projected intensity. In some embodiments, light at the edge of the field of view can have a higher intensity than the pattern in the center to produce a uniform intensity at the center of the points that reflect light in accordance with the cosine law of radiation measurement. For example, points at the edge can have a higher center intensity than points at the center of the field of view so that the reflection of points at the edge is balanced with the reflection of points at the center. Alternatively, the intensity at another arbitrarily selected location (e.g., the edge, the center, a point between the edge and the center, etc.) can be associated with an intensity at the center of the pattern that is higher than another arbitrarily selected location.

As shown in FIG2C , exemplary embodiment 220 illustrates another example of a non-uniform intensity field. As shown by graph 222, the non-uniform intensity field may include discrete regions 224 of higher intensity light and discrete regions 226 of lower intensity light (e.g., non-zero intensity light) in a stepped pattern. In other words, all areas of the field of view are at least partially illuminated, but some areas are illuminated less than other areas. In this case, discrete regions 224 may be concentrated areas that are illuminated, and discrete regions 226 may be areas that are also illuminated but with less light than discrete regions 224. For example, discrete region 226 may be associated with less than 10% of the illumination intensity relative to discrete region 224, thereby enabling discrete region 226 to return a greater number of photons to sensor system 105 at a critical distance compared to the case where a uniform intensity field is used. Additionally or alternatively, discrete region 226 may be associated with less than 90% illumination intensity, less than 80% illumination intensity, between 80% and 10% illumination intensity, and/or the like relative to discrete region 204. In some embodiments, sensor system 105 may be able to perform sensing at discrete region 226. For example, when a non-zero intensity is provided at discrete region 226 and the object is within a threshold, sensor system 105 can determine the extent of the object and/or portion thereof across the field of view. In this manner, sensor system 105 can achieve both depth sensing using time-of-flight measurements performed on discrete region 224 and imaging using measurements performed on discrete region 226. Furthermore, sensor system 105 achieves improved resolution of three-dimensional measurements of the object based on providing at least some light across the entire field of view, relative to, for example, a non-uniform intensity field where portions of the field of view do not include light for performing measurements.

As shown in FIG2D , exemplary embodiment 230 illustrates another example of a non-uniform intensity field for a scanning type sensor system 105 (e.g., a scanning lidar system). As shown by graph 232, the non-uniform intensity field may include discrete lines 234 of higher intensity light and gaps 236 of lower intensity light (e.g., zero intensity light) in a step pattern. For example, the optical transmitter 115 may provide a uniform scan line, and the light shaping optical element 120 may shape the uniform scan line into a non-uniform scan line including discrete lines 234 (i.e., line segments or intensity points forming a line) and gaps 236. In another example, the gaps 236 may be partially illuminated with a lesser intensity than the discrete lines 234, while non-gaps 236 have zero intensity light. In this case, the sensor system 105 may scan horizontally across the field of view by providing discrete lines 234 to scan the field of view. Additionally or alternatively, the sensor or system 105 may provide horizontal discrete lines 234 and gaps 236 and may scan vertically to scan the field of view to perform depth sensing measurements. In this way, the sensor system 105 increases the range used for scanning depth sensing relative to using lower intensity continuous lines to scan the field of view.

As shown in FIG2E , exemplary embodiment 240 illustrates another example of a non-uniform intensity field. As shown by graph 242, the non-uniform intensity field may include a continuous pattern (e.g., a sinusoidal-based pattern) of light intensity formed by a ring-shaped pattern of light (e.g., which forms an interference pattern of light). In this case, the continuous pattern may include concentrated areas 244 of higher intensity light and non-concentrated areas 246 of lower intensity.

As shown in FIG2F , exemplary embodiment 250 illustrates examples of non-uniform intensity fields and uniform intensity fields. As shown by graph 251 , a non-uniform intensity field may include discrete regions of higher intensity light and discrete regions of lower intensity light (e.g., zero intensity light) in a stepped pattern, and may be associated with a total intensity less than a threshold value (although it may include discrete regions of high intensity light exceeding the threshold value). In contrast, as shown by graph 255 , a uniform intensity field may be a constant intensity (e.g., non-zero intensity) field that may be associated with an intensity less than a threshold value. In this case, the sensor system 105 may transmit a first light beam using a non-uniform intensity field to perform depth sensing and a second light beam using a uniform intensity field to perform image sensing. Additionally or alternatively, the sensor system 105 may transmit a single light beam and may include a light shaping optical element (e.g., a light shaping optical element of the light shaping optical element 120) to split the single light beam into a first light beam for shaping into a non-uniform intensity field and a second light beam for diffusing into a uniform intensity field. In some embodiments, the sensor system 105 may include multiple VCSEL arrays to provide multiple light beams, and the multiple VCSEL arrays may be pulsed simultaneously, sequentially, and/or the like to capture both a depth point cloud and a two-dimensional image using a single image sensor of the optical receiver 130. In this way, the sensor system 105 can achieve both depth sensing using time-of-flight measurements performed on a non-uniform intensity field and imaging using measurements performed on a uniform intensity field. Although some embodiments are described herein in terms of a set of specific patterns, other patterns may be possible and may be different from those described herein. For example, other patterns may include other repeating patterns of clustered areas, other non-repeating patterns of clustered areas, regular patterns of clustered areas, irregular patterns of clustered areas, and/or the like. In some embodiments, the sensor system 105 may project multiple different patterns (e.g., for separate imaging, for combination to produce a single image, etc.).

2G, exemplary embodiment 260 illustrates an example of a non-uniform intensity field. As shown by graph 262, the non-uniform intensity field may include discrete regions 264 having higher intensity light based on directing a higher density of intensity points to discrete regions 264 relative to regions 266 by light shaping optical elements.

As indicated above, Figures 2A to 2G are provided only as one or more examples. Other examples may be different from the examples described with respect to Figures 2A to 2G.

Figures 3A to 3C are diagrams of exemplary implementations 300 to 320 of non-uniform intensity light fields that can be shaped by the light shaping optical element 120.

As shown in FIG. 3A and by exemplary embodiment 300, some patterns may have intensities that vary from a concentrated light intensity in a first set of regions to a lower light intensity in a second set of regions (e.g., greater than a critical light intensity), where the intensity varies with a function (e.g., a sine function). In this case, the critical light intensity may be between 10% and 90% of the intensity at the highest concentration point. In contrast, as shown by FIG. 3B and by exemplary embodiment 310, uniform intensity points with a uniform intensity field between points may be used. In contrast, as shown by FIG. 3C, a non-uniform intensity field may be provided in three dimensions. In another example, the intensity may be varied to produce a line pattern, a repeating pattern, a non-repeating pattern, a plurality of different patterns, or combinations thereof and/or the like.

As indicated above, Figures 3A to 3C are provided only as one or more examples. Other examples may be different from the examples described with respect to Figures 3A to 3C.

In this way, by creating a non-uniform intensity field, the sensor system 105 can ensure that a threshold number of photons can be received during a measurement without increasing the overall intensity, thereby enabling accurate depth sensing at an increased range relative to using uniform intensity.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementation scheme to the precise form disclosed. Modifications and variations may be made in light of the above disclosure, or may be obtained from the practice of the implementation scheme.

As used herein, meeting a threshold value means that a value is greater than a threshold value, more than a threshold value, higher than a threshold value, greater than or equal to a threshold value, less than a threshold value, less than a threshold value, lower than a threshold value, less than or equal to a threshold value, equal to a threshold value, etc., depending on the context.

Even though particular combinations of features are recited in the claims and/or disclosed in the specification, such combinations are not intended to limit the disclosure of the various embodiments. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may depend directly on only one claim, the disclosure of the various embodiments includes each dependent claim in combination with every other claim in the claim set.

Unless explicitly stated as such, any element, action or instruction used herein shall not be interpreted as critical or essential. In addition, as used herein, the articles "a" and "an" are intended to include one or more items and can be used interchangeably with "one or more". In addition, as used herein, the term "group" is intended to include one or more items (e.g., related items, unrelated items, combinations of related and unrelated items, etc.), and can be used interchangeably with "one or more". In the case of only one item, the phrase "only one" or similar language is used. In addition, as used herein, the terms "has", "have", "having", etc. are intended to be open terms. In addition, the phrase "based on" is intended to mean "based at least in part on", unless otherwise explicitly stated.

100: Implementation plan 105: Sensor system 110: Transmitter system 115: Optical transmitter 120: Light shaping optical element 125: Receiver system 130: Optical receiver 135: Filter 140: Lens 145: Component symbol 150: Object 155: Component symbol 160: Component symbol 200: Implementation plan 202: Diagram 204: Discrete region 206: Discrete region 210: Implementation plan 212: Diagram 214: Discrete region 216: Discrete Scattered area 220: Implementation plan 222: Diagram 224: Scattered area 226: Scattered area 230: Implementation plan 232: Diagram 234: Scattered line 236: Gap 240: Implementation plan 242: Diagram 244: Clustered area 246: Non-clustered area 250: Implementation plan 251: Diagram 255: Diagram 260: Implementation plan 262: Diagram 264: Scattered area 266: Area 300: Implementation plan 310: Implementation plan 320: Implementation plan

[FIG. 1A] and [FIG. 1B] are diagrams of exemplary embodiments described herein.

[Figure 2A] to [Figure 2G] are diagrams of uneven intensity fields.

[Figure 3A] to [Figure 3C] are diagrams of uneven intensity fields.

100: Implementation plan

105:Sensor system

110: Transmitter system

115:Optical transmitter

120: Light shaping optical elements

125:Receiver system

130: Optical receiver

135:Filter

140: Lens

145: Component symbol

150: Objects

Claims (19)

A light shaping optical element, comprising: a structure, wherein the structure is constructed to receive one or more input light beams having a uniform intensity field and less than a critical total intensity; and wherein the structure is constructed to shape the one or more input light beams to form one or more output light beams having a non-uniform intensity field and less than the critical total intensity; wherein the critical total intensity is a critical value of at least one or more of a specific divergence angle, a specific pulse duration, and a specific exposure direction. A light shaping optical element as claimed in claim 1, wherein the non-uniform intensity field includes a set of higher intensity light regions and a set of lower intensity light regions. A light shaping optical element as claimed in claim 1, wherein the non-uniform intensity field is at least partially illuminated. A light shaping optical element as claimed in claim 1, wherein at least a portion of the non-uniform intensity field is not illuminated. A light shaping optical element as claimed in claim 1, wherein the non-uniform intensity field forms a pattern, and wherein the pattern is at least one of the following: a dot pattern, a grid pattern, a ring pattern, an interference pattern, a step pattern, a sawtooth pattern, a continuous pattern, a sine-based pattern. The light shaping optical element of claim 1, wherein the one or more input light beams are uniform scanning lines of the lidar system, and the one or more output light beams form non-uniform scanning lines of the lidar system. A time-of-flight measurement system comprising: an optical transmitter for providing a light beam directed toward an object, wherein the light beam is associated with a constant intensity across a field of view; a light shaping optical element for focusing the light beam into one or more focusing regions, wherein the one or more focusing regions of the field of view are associated with a higher light concentration than one or more other regions of the field of view, and wherein the total intensity of the one or more focusing regions meets a threshold of at least one or more of a specific divergence angle, a specific pulse duration, and a specific exposure direction; and an optical receiver for receiving a reflection of the light beam reflected from the object and performing a plurality of time-of-flight measurements on the light beam. A flight time measurement system as claimed in claim 7, wherein the light shaping optical element is an engineered diffuser. A flight time measurement system as claimed in claim 7, wherein the system is constructed to illuminate the object using the light beam so that the object is illuminated unevenly by the one or more concentrated areas. A flight time measurement system as claimed in claim 7, wherein the optical receiver is constructed to perform flight time measurement for each of the one or more concentrated areas of the field of view. The flight time measurement system of claim 7, further comprising: a processor configured to generate a depth point cloud of the object using the plurality of flight time measurements. A flight time measurement system as claimed in claim 7, wherein the one or more concentrated areas of the field of view form a plurality of intensity points, and wherein the plurality of intensity points are associated with a critical density. A flight time measurement system as claimed in claim 7, wherein the system is configured to determine that the plurality of flight time measurements are greater than a threshold distance of the system relative to the object. The time-of-flight measurement system of claim 7, further comprising: a processor for generating a three-dimensional representation of the object based on the plurality of time-of-flight measurements and imaging measurements of another light beam provided by the optical transmitter, wherein the other light beam is associated with a constant intensity and is directed toward the object without being shaped into one or more focusing regions. A flight time measurement system as claimed in claim 7, wherein the optical receiver is a sensor array comprising a plurality of sensor elements, and wherein each sensor element of the plurality of sensor elements is constructed to produce a flight time measurement of the plurality of flight time measurements. An optical element, comprising: a substrate; and a light shaping optical element, for providing a non-uniform patterned intensity light beam, wherein the non-uniform patterned intensity light beam comprises a set of first regions having a first intensity and a set of second regions having a second intensity, wherein the second intensity is between 10% and 90% of the first intensity, and wherein the total intensity of the non-uniform patterned intensity light beam is less than a threshold value of at least one or more of a specific divergence angle, a specific pulse duration, and a specific exposure direction. As claimed in claim 16, the optical element is a component of a lidar system. The optical element of claim 16 further comprises: an array of sensor elements disposed on the substrate. An optical element as claimed in claim 18, wherein the array of sensor elements is constructed to determine a plurality of time-of-flight measurements of the non-uniform patterned intensity beam to determine a plurality of distances associated with the object.